Hello, I have just got ahold of a 94 GT convertible. Very nice ride for a car that age. However there is a humming noise at highway speed. Sort of a grinding noise. I checked the wheels for bearings, but there is no movement. However the driver side wheel does not turn smoothly as the other. It seems to be catching on the brake pad. Very slightly but noticeable. I am no mechanic but do change my own oil. I read on here it may be a warped rotor. Do I get new ones, or turn the old ones, do I do both, and lastly do I need new pads? They are new, 3,000 miles or so on them. Thank you for any advice.